The former Vatican treasurer insists his innocence against all allegations made against him.

But Australia's most senior Catholic cleric could face up to 50 years in jail.

He will have his chance to clear his name at appeal dates scheduled for June 5 and 6.

The 77-year old’s legal team has filed three grounds of appeal against the verdict.

One appeal lodged is that the verdict was “unreasonable” because it relied on the “word of one complainant alone.”

“The verdicts are unreasonable and cannot be supported, having regard to the evidence," the appeal reads.

"On the whole evidence, including unchallenged exculpatory evidence from more than 20 crown witnesses, it was not open to the jury to be satisfied beyond reasonable doubt on the word of the complainant alone.”